Thermostat



Aug. 13, 1929. F. scHAUM THERIOSTAT Filed July 2. 192'7'l Patented Aug.13, 1929.

STATE FLETCHER SCEAUM, OF PEILEEiaEA,

THERMOSTAT.

respond more quickly to the changes in emperature than will the ordinaryforms of thermostat now in use.

Still another object of the invention is to provide a thermostat that isso arranged that lo it will overcome the usual lag that takes placebetween the action of the thermostat and the source of heat that affectsthe thermostat.

Still another object of the invention is to provide a thermostat whereinthe contact posts opposite the bi-metal arm may-oscillate through asmall amplitude in its movement so that the lai-metal in retracting willnot have to return through its full former 2G amplitude to make contactwith its opposing contact post.

Still another object of the invention is to provide a thermostat thatmay be easily ad- )usted to operate at diiierent temperatures and at thesame time provide an oscilliating yoke to quicken the action of thethermostat.

lVith these and other objects in view, the invention consists in certainnew .and novel arrangements and combination of parts, as will behereinafter more fully described and pointed out in the claims.

Referring now to the drawings showing a preferred embodiment of theinvention.

Fig. l is a plan view oi my improved thermostat, and

Fig. 2 is a similar detail view of the oscillating yoke and controllingarm, the oscillating yoke being shown at its limit of movement.

Referring now more particularly to the several views, there is shown abase l, which may be of any common form of dielectric or this may be'ofwood if so desired, but if the latter, the binding posts 2, 3 and 4 mustbe properly insulated therefrom.

l have not shown any input connections to these binding posts 2, 3 and4, but it will be understood that any wire leading to the post 3, willbe a common pole to the other two posts.

Properly mounted on the base l, is a small retaining post 5, in whichwill be mounted a coil of bi-metal 6 that will expand under theinduences of heat, the heat of course causing `he coil to uncoil andthus swing the arm or end of the coil to the right. On the other aand, acooling temperature will cause the coil to contract and swing the armtowards the left, as is common in all forms of thermostats.

At the end of this arm 7, may be the small platinum points 8 as is alsocommon to thermostats. Located beneath the coil 6 is a small plate 9,which is provided with four slots l0- at its oplposite corners, throughwhich pass the screws ll which screws are firmly secured in the base l..At one side of the plate 9, is a small retaining member l2, in which isfastened the bolt 13, which in turn is threaded within the post le, theknurled knob l5 on the bolt may thus be used to laterally adjust thisplate 9, so that the thermostat will respond desired temperaturea Alongthe bottom edge of the plate and centrally thereoi` may be formed thearrow or pointer l@ beneath which, and secured to the base is the plate17 on which will appear the different graduations in degrees ortemperature.

One of the important features ot the invention is the small yoke 18 thatis pivoted as at 19, so that ig may pivot or oscillate through smallamplitude et movement.

This yoke 18, however, will only pivot or oscillate when actuated by amovement of the arm 7 and will remain in its moved position until againactuated by a movement in the opposite direction of the arm. ln otherwords, although it is pivotally mounted at 19, it will retain itsposition until moved in either direction by movement of the arm 7.

This yoke 18 may be ot metal and is provided with two small pieces ofdielectric 20 on its opposite arms, so as to properly insulate the yokearms 2l and 22 from the body. Fitted within the arm 2l is the smallthreaded post 23, while a similar post 24 is threaded within the arm 22.Binding nuts 25 are provided for each post, so that connecting wires 26and 27 may lead to the binding posts 4.- and 2 respectively.

Referring again to the yoke 18, a small projection 28 is seen at thebottom thereof which in turn normally extends between the two limitingscrews 29, which in turn are threaded within the respective posts 30.These posts 29 may be regulated so that the yoke 18 is limited in itsoscillation in both directions.

It will be remembered that the plate 9 as a whole is laterally movableand it will be also seen that contacting posts 23 and 24 are adjustableas well as the limiting screws 29, so that a fine degree of adjustmentmay be made with the plate and its yoke with relation to the coil 6 andits arm 7. The operation of the device is as follows:

Supposing that to the binding posts 3 and 4 lead wires (not shown)extend to a solenoid or other actuating means, which in turn will beconnected to a heat supply or whatever is desired to be controlled bythe thermostat. Also lead wires will extend from 3 and 2 to this orother regulating means. Now supposing that the temperature rises, thecoil 6 will expand and swing its arm 7 to the position shown in Fig. 2.This will complete the circuit from the post 3 through the arm 23 andfrom the binding post 4 to the instrument to operate the desiredmechanism for cutting off the heat.

It will also be noticed that when the coil 6 extends and contacts withthe post 23, it will also oscillate the pivotal yoke slight to the rightas shown in Fig. 2 and will in this manner move the post 24 over to thepoint where the arm 7 will contact with the same when the arm 7 hasreturned to its position shown in Fig. 1. The arm 7 therefore does nothave to travel the distance between the platinum point 8 and the arm 24,(Fig. l), which it ordinarily would have to travel if the yoke 18 werenot pivoted and had not swung to the right.

As soon, therefore, as the arm 7 reaches its normal position, (vertical)it 4will then form the electrical contact through the arm 24 andcomplete the circuit through the instrument connected through thebinding posts 2 and 3.

lf the temperature continues to drop, the arm 7 will of course continueto move to `thc left and oscillate the yoke in the opposite directionshown in Fig. 2 and cause the yoke to assume a position 'ust opposite tothat shown in Fig. 2, so t at when the arm 7 again returns to the normalposition, the yoke being swung to the left would contact again with thearm 23 to thus operate the instruments connected to the leads 3 and 4.

From this it will be seen that the thermostat is one of delicateoperation and quick action, and as it will operate more quickly than theordinary thermostat, it will overcome the lag that is generally incidentto other forms of thermostat controls.

It will also be seen that whether the bimetal arm swin s to the right orleft, it will oscillate the yo e with it, so that when the arm againreturns to its vertical position, it

will contact with the opposing post more quickly than if the yoke andthe posts 23 and 24 were stationary.

Furthermore, it will be seen that the thermostat is one of simpleconstruction, there being but one moving part beside the coil, and onlyparts that need to be insulated are the arms 21 and 22, as otherwise, ofcourse, the circuits would be complete through the yoke 18.

I have found that the thermostat is one that may be easily adjusted andafter one advjustment, needs no further attention. It will also `operateunder very slight changes in temperature due to the pivotal arrangementof the yoke.

This is important, 'as the slight variations in temperature will causefirst one circuit and then the other to operate, so that there will beno lag between operations and w1ll not let, say the fire in the heateror under the boilers, get too low or too high between operations of thethermostat.

Many slight changes might be made without in any way departing from thesp1r1t and scope of the invention.

Having thus described my invention, what I claim vas new and desire tosecure by Letters Patent is 1. A thermostat comprising a base, a bimetalcoil mounted on said base, a pivotalv yokeI straddling the end of saidcoil, the opposite arms of said yoke being lnsulated from the yoke, thetwo arms and the said coil adapted to be placed in an electric circuitwhereby the coil will form a common pole for either circuit, and aswinging of the end of the coil in either direction will close one ofsaid circuits and slightly oscillate said yoke to bring. thenon-contacting arm closer to the end of the coil.

2. A thermostat comprising a base, a heat actuated metal coil mounted onsaid base, a pivotal yoke straddling the end of said coil, the oppositearms of said yoke being insulated from the body of said yoke and fromeach other', posts in each of said arms, the `said posts and the arm ofsaid coil adapted ato be connected to electric circuits so that the coilwill be a common pole with either post and a movement of said arm ineither direction completing an el'ectric circuit to oscillate said yoketo bring the non-contacting post closer to said swinging arm than if theyoke remained stationary.

3. A thermostat comprising a base, a thermo-controlled coil having avertically extending arm, a pivotal member having two opposite postsstraddling said arm, said posts insulated from each other, the thermoarm and the said posts adapted to be electrically connected so that thethermo arm is a common pole for either post, the pivotal member adaptedto oscillate by an expansion or contraction of said coil so that areturn arm on expanding contacting with one of said posts to close anelectric circuit, and also oscillating said pivotal member to cause theother ot said posts to follow the arm in its swing, so that said thermoarm will more quickly contact with the latter of said posts on areturning movement than would be the case if the pivotal member had notoscillated.

5. A thermostat comprising a base, a thermo-controlled coil having avertically oppositely disposed adjust' common pole with both of saidposts, the

operation of said arm in one direction contacting with one of said poststo close an electric circuit and also causing the opposite post tofollow it in its swing, so that a swinging ot the arm in the otherdirection will close the electric circuit with the other of said postsmore quickly than had the last mentioned post not followed the coil armin Iits first movement.

6. A thermostat comprising a base, a thermo-arm mounted on said base,two movable electric posts straddling said arm, the thermo arm beingwired so that it will form la common pole with both of said posts, thesaid thermo arm when expanding swinging to the right to close onecircuit and move bot-h of said posts so that on a cooling of the arm anda swinging of the same in the 'opposite direction, it will contact withthe other of said posts to close the circuit when the said arm reaches,substantially a vertical position.

7. A thermostat comprising a base, a

thermo arm mounted on said base, movable electric contact postsstraddling said arm and wired so that the thermo arm is a common pole toeither post, said thermo arm when swinging in one direction contactingwith one of said posts to close the circuit, and causing the other postto follow said thermo arm in its movement so that an opposite swingingof said arm will cause the thermo arm to quickly contact with thefollowing post to close said posts in either direction.

8. A thermostat comprising a thermo coil arm, two oppositely disposedcontact posts straddling the coil arm, said posts being eapable of beingset in a horizontal predetermined position and the said posts beinginsulated from each other, the coil arm and the said posts being soelectrically connected that the said coil arnris a common pole witheither of said posts, and a swinging movement of the said arm in eitherdirection contacting with one post and causing the other post to followit, whereby, on a retracting movement of said arm, it will more quicklyovertake the other post than had the two posts not moved with theinitial swinging or said arm.

9. A thermostat comprising a base, a thermo coil on said base, a yokepivotally mounted beneath the end of said coil, said yoke also movablehorizontally, said yoke having two adjustable posts insulated from eachother, the two posts and thermo coil being so electrically connectedthat the thermo coil is a common pole for either of said posts, saidthermo arm adapted to contact with either one of said posts to therebyclose a respective circuit, said arm also causing said yoke to oscillatewhereby a retracting movement of the said coil arm will more quicklycontact with one of said post arms than had said yoke remainedstationary.

l0. A thermostat comprising a base, a

thermo coil mounted on said base, said coil having a vertical armextending therefrom, a plate mounted beneath the coil, capable ofhorizontal adjustment, a pivotal yoke on said plate, means for limitingthe oscillations of said yoke, the upper ends of said yoke beinginsulated from the rbody of the yoke, the thermo arm and said ends beingso electrically connected that the thermo arm is a common pole for eachof said ends of the yoke, and a swinging of said arm in either directionclosing the circuit through one o the ends of said yoke and causing theyoke to oscillate whereby the other end of said yoke will more quicklycontact with said arm on a retracting movement of said arm than would bethe case it the yoke had remained stationary.

l1. A thermostat comprising a thermo controlled arm, a platehorizontally movable beneath the said arm, a pivotal member secured tosaid plate and having oppositely disposed insulated posts straddlingsaid arm, means for regulating the distance between the posts and saidarm, means :tor limiting the pivotal movement of said member, means fordetermining the horizontal position of said plate and said pivotal1member, said thermo arm and said posts being so wired as to make thethermo arm a common pole for either post of the pivotal member, and amovement of said arm causing the pivotal member to swing in thedirection of the movement of said arm whereby a return movement of thearm will quickly'overtake the arm that lies in the path of theretracting thermo arm.

12. A thermostat comprising a base, a

thermo arm, a horizontally adjustable movable plate beneath the arm, apivotal yoke on said plate and straddling said arm, binding contactposts Von. said yoke insulated from each other, the thermo arm adaptedto close an electric circuit with either of said posts, the said thermoarm also causing a small oscillation of the arm in either direction sothat a return movement of said arm will quickly contact with the armthat has followed the arm in its swinging position to thereby close theother of said circuits.

13. A thermostat comprising a thermo arm and a pivotal yoke straddlingsaid arm, two electric contacts on said yoke and insulated from eachother, the thermo arm arranged in a circuit that is common to eitherelectric contact, and a swinging of the arm pushing one electric Contactin one direction and causing the other electric contact to follow thearm whereby a return movement of the thermo arm will quickly contactwith the electric contact that followed the arm in its movement, and acontinued movement of the arm causingthe yoke to oscillate in adirection reverse to the first oscillating movement of the yoke.

14. A thermostat comprising a base, a thermo arm, a yoke beneath the armcapable of an oscillatory movement, said yoke and thermo arm arranged inan electric circuit whereb the thermo arm is common to both ends o theyoke, and a movement of the thermo arm in one direction completing one f

